of the speed by means of the time and distance diagrams is more definite. When the resistances of the model have been obtained at several speeds, varying in some cases from 50 to 1,000 feet per minute, the speeds are set off in suitable units along a base line, and for every speed at which resistance is measured, the resistance is set off to scale as an ordinate value at those speeds. A line passing through these spots forms the "curve of resistance," from which the resistance experienced by the model at the given trial speeds or any intermediate speed can be ascertained. The resistance being known, the power required to overcome resistance and drive the actual ship at any given speed is easily deduced by applying the rule before described as the law of comparison.--_The Steamship._ * * * * * THE SHIP IN THE NEW FRENCH BALLET OF THE "TEMPEST." A new ballet, entitled the "Tempest," by Messrs. Barbier and Thomas, has recently been put upon the stage of the Opera at Paris with superb settings. One of the most important of the several tableaux exhibited is the last one of the third act, in which appears a vessel of unusual dimensions for the stage, and which leaves far behind it the celebrated ships of the "Corsaire" and "L'Africaine." This vessel, starting from the back of the stage, advances majestically, describes a wide circle, and stops in front of the prompter's box. [Illustration: FIG. 1.--SHIP OF THE "TEMPEST," IN PROCESS OF CONSTRUCTION.] [Illustration: FIG. 2.--SETTING OF THE SCENERY BEFORE AND AFTER THE APPEARANCE OF THE SHIP.] As the structure of this vessel and the mechanism by which it is moved are a little out of the ordinary, we shall give some details in regard to them. First, the sea is represented by four parallel strips of water, each formed of a vertical wooden frame entirely free in its movements (Fig. 2). The ship (Figs. 1, 2, 3, 4 and 5) is carried by wheels that roll over the floor of the stage. It is guided in its motion by two grooved bronze wheels and by a rail formed of a simple reversed T-iron which is fixed to the floor by bolts. In measure as it advances, the strips of water open in the center to allow it to pass, and, as the vessel itself is covered up to the water line with painted canvas imitating the sea, it has the appearance of cleaving the waves. As soon as it has passed, the three strips of water in the rear rise slightly. When the vessel reaches the first of the strips, the three other strips, at first juxtaposed against the preceding, spread out and thus increase the extent of the sea, while the inclined plane of the preceding tableau advances in order to make place for the vessel. The shifting of this inclined place is effected by simply pulling upon the carpet that covers it, and which enters a groove in the floor in front of the prompter's box. At this moment, the entire stage seems to be in motion, and the effect is very striking.